class_docstr: Base class for 3D cameras supporting orthographic and
  perspective projections.
  
  Parameters
  ----------
  fov : float
      Field of view. Default 60.0.
  scale_factor : scalar
      A measure for the scale/range of the scene that the camera
      should show. The exact meaning differs per camera type.
  **kwargs : dict
      Keyword arguments to pass to `BaseCamera`.
docstr: The distance of the near clipping plane from the camera's position.
docstr_tok: ["The","distance","of","the","near","clipping","plane","from","the","camera","'s","position","."]
code: def near_clip_distance(self):
      """The distance of the near clipping plane from the camera's position."""
      return self._near_clip_distance
  
imports: from __future__ import division
  import math
  import numpy
  from .base_camera import BaseCamera
  from ...util import keys, transforms
  from ...visuals.transforms import MatrixTransform
label_desc: Use image node_id 5 for calling the PerspectiveCamera obj's underlying member method code with example usage: obj.near_clip_distance() and returns: self